1. Field of the Invention
The present invention relates to a wide-viewing-angle imaging lens assembly, and more particularly, to a wide-viewing-angle imaging lens assembly that is compact in size with a large angle of view.
2. Description of the Prior Art
In recent years, optical imaging lenses have been used in a wider range of products, and in particular, they are used in the following products for example: mobile phone cameras, webcams, vehicle cameras, security surveillance cameras and electronic game devices. The sensor of a general imaging lens is none other than CCD (charge coupled device) or CMOS device (Complementary Metal Oxide Semiconductor device). As advances in semiconductor manufacturing technology have allowed the pixel size of sensors to be reduced, and the resolution of compact imaging lenses has gradually increased, there is an increasing demand for compact imaging lenses featuring better image quality.
Imaging lenses used in vehicle cameras, security surveillance cameras or electronic game devices typically require a larger field of view, to capture an image of a larger area at one time. A conventional imaging lens assembly with a large field of view generally comprises a front lens group with negative refractive power and a rear lens group with positive refractive power; such an arrangement forms a so-called inverse telephoto lens which features a wide field of view. One example is shown in U.S. Pat. No. 7,446,955, which has disclosed a lens assembly comprising four lens elements wherein the front lens group has negative refractive power and the rear lens group has positive refractive power. Such an arrangement of lens elements allows a lens assembly to have a larger field of view; however, with the rear lens group having only one lens element, aberrations of the system cannot be favorably corrected. Moreover, vehicles equipped with backup cameras have become more and more common, and there is a trend toward high-resolution, wide-angle lenses for backup cameras. As a result, there remains a need to provide an imaging lens assembly which has a wide field of view, high image quality, and a reduced total track length.